1. Field of the Invention
The present invention relates to a continuous package train having a plurality of packages connected in series at least in one direction in a belt-like form, each package containing a deoxidizing agent. The invention also is concerned with an apparatus for severing the packages of deoxidizing agent from such a train of packages.
2. Description of the Related Art
In order to prevent goods such as foodstuffs and medical drugs from being deteriorated during long storage, it has been proposed to put a package of an agent capable of absorbing oxygen (referred to as deoxidizing agent, hereinunder) in a hermetic foodstuffs or drug container such as a sack or a can having walls of a high gas barrier effect. This measure has became an established technique particularly in the field of preservation of foodstuffs, and is finding spreading use in various fields which require elimination of all kinds of unfavorable effect which may be caused by the presence of oxygen.
Systems are also proposed for automatically producing goods such as foodstuffs and medical drugs sealed in hermetic containers together with packages of a deoxidizing agent. For the purpose of achieving a high production efficiency, such production systems usually employ a package train of the deoxidizing agent in which a plurality of packages each containing the deoxidizing agent are connected in series in a form like a belt. The packages are severed one by one from the package train by an automatic severing apparatus and independent packages thus obtained are charged into successive containers of the goods.
FIG. 2 schematically shows the manner in which the packages are successively severed in a process for producing sealed goods. A package train generally denoted by 10 has a plurality of packages containing a deoxidizing agent and connected in series through sealed connecting webs. An automatic severing apparatus, which is generally designated by a reference numeral 12, has thickness sensors 14 which measure the thickness of the package train so as to distinguish the thin sealed connecting webs from the packages which are charged with the deoxidizing agent and, hence, are large in thickness. The apparatus 12 also has a cutter 16 which is operated in synchronism with the passage of the package train in accordance with the output from the thickness sensors 14 so as to cut the package train at successive sealed connecting webs, whereby the packages are severed one by one. The package train is folded at its connecting webs such that the successive packages are stacked on one another, and are stored in a case 18 with its trailing end placed on the bottom of the container such as to be continuously fed into the severing apparatus 12.
This known system, however, tends to suffer from a disadvantage in that the fold of the sealed connecting web cannot be perfectly straightened before it reaches the thickness sensors 14 of the automatic severing apparatus, with the result that the thickness sensor fails to detect the sealed connecting web so as to miss the timing for actuating the cutter 16. This problem is serious particularly in the case where the package has a layer of plastic film coating on the surface thereof. The same problem is encountered also when the detection of the sealed connecting web is effected by means of a photoelectric tube which can detect a specific mark on the package train. The use of a layer of plastic film coating on the package is disadvantageous also in that the package train cannot easily be folded at the sealed connecting webs due to a large resiliency exhibited by the plastic film, which makes it difficult to store a long package train in folded state.
Usually, a package of deoxidizing agent exhibits a tendency to absorb oxygen when left in the air, so that it is preferably kept away from the air unless it is not going to be charged in a container of goods such as foodstuffs. The known package train, when stored in a folded state, tends to allow the ambient air to flow into the spaces between adjacent packages stacked in layers, so that the packages undesirably absorb oxygen, with the result that the oxygen absorbability is impaired before the packages are severed by the severing apparatus.
The stored packages which have absorbed oxygen generate heat which is accumulated due to the high density of the stack of successive packages and in turn vaporizes the moisture inherently contained in the deoxidation agent so as to accelerate the impairment of its oxygen absorbability.
For these reasons, the length of the package train 10 which has to be fed to a severing apparatus is undesirably limited.